Systems and methods for providing a haptic manipulandum

ABSTRACT

Systems and methods for providing a haptic manipulandum are described. In one described system, a lever arm is pivotably coupled to a housing, and configured to apply a processor-controlled force to a substantially-spherical manipulandum to provide a haptic effect. The described system may include a processor in communication with an actuator for providing the haptic effect.

RELATED APPLICATIONS

This application claims priority to, and incorporates by referencehereto, co-pending U.S. Provisional Patent Application Ser. No.60/475,809, filed Jun. 3, 2003, and entitled “Haptic Trackball.”

FIELD OF THE INVENTION

The present invention generally relates to providing haptic feedback.The present invention more particularly relates to systems and methodsfor providing a haptic manipulandum, such as a trackball apparatus.

BACKGROUND

Electronic device manufacturers strive to produce a rich interface forusers. Conventional devices utilize visual and auditory cues to providefeedback to a user. In some interface devices, kinesthetic and/orvibrotactile feedback (such as, without limitation, active and resistiveforce feedback, vibration, texture, heat, etc.) may also be provided tothe user, more generally known collectively as “haptic feedback.” Hapticfeedback can provide cues that enhance and simplify the user interface.

Known systems and methods have attempted to provide haptic effects to atrackball device. (See, for example, U.S. Pat. No. 5,781,172, entitled“Data Input Device for Use With a Data Processing Apparatus and a DataProcessing Apparatus Provided With Such a Device” by F. Engel et al.;U.S. Pat. No. 5,914,705, entitled “Apparatus and Method for ProvidingDetent-Like Tactile Feedback” by B. Johnson et al.; and U.S. Pat. No.6,480,185, entitled “Electronic Device With Trackball User Input” by H.Kiljander et al.) Such systems and methods are not effective for certaindesign criteria and approaches.

SUMMARY

Embodiments of the present invention comprise systems and methods forproviding a haptic manipulandum. One embodiment of the present inventioncomprises a housing, a substantially-spherical manipulandum, and a leverarm pivotably coupled to the housing. The lever arm may be configured toapply a processor-controlled force to the substantially-sphericalmanipulandum to provide a haptic effect. The resulting force may cause aresistance, which can be controlled to deliver haptic effects to asubstantially-spherical manipulandum, such as a trackball.

This exemplary embodiment is mentioned not to limit or define theinvention, but to provide an example of an embodiment of the inventionto aid understanding thereof. Exemplary embodiments are discussed in theDetailed Description, and further description of the invention isprovided there. Advantages offered by the various embodiments of thepresent invention may be further understood by examining thisspecification.

BRIEF DESCRIPTION OF THE FIGURES

These and other features, aspects, and advantages of the presentinvention are better understood when the following Detailed Descriptionis read with reference to the accompanying drawings, wherein:

FIG. 1 illustrates a perspective view of a trackball deviceincorporating one embodiment of the present invention;

FIG. 2 is a cutaway elevation view of a sub-assembly comprising a firstactuator and a second actuator according to the embodiment shown in FIG.1;

FIG. 3 is a plan view of a trackball device according to the embodimentof the present invention shown in FIG. 1;

FIG. 4 is a cutaway perspective view of a trackball device comprising asensing device according to an embodiment of the present invention;

FIG. 5 is a block diagram, illustrating one embodiment of a trackballdevice according to the present invention; and

FIG. 6 is a flowchart, illustrating a process of navigating emailutilizing a trackball pointing device utilizing one embodiment of thepresent invention in communication with a personal computer.

DETAILED DESCRIPTION

Embodiments of the present invention provide systems and methods forproviding a haptic manipulandum. A device may incorporate a variety oftechnologies for providing haptic feedback, including both active andresistive devices. Active haptic feedback devices, including, forexample, devices incorporating motors, generally add energy to a system;resistive devices, such as devices incorporating brakes, generallyremove energy from the system.

Active haptic actuators may utilize, for example, alternating current(AC) or direct current (DC) electric motors and/or generators. Resistivehaptic actuators may utilize, for example, electromagnetic brakes,magnetic particle brakes, magnetorheologic or electrorheologic brakes,or magnetic (non-friction) brakes. Electromagnetic brakes utilize amagnetic core, a coil, and a magnetic target. When a current is appliedto the coil, the magnetic core acts upon the magnetic target. Magneticparticle brakes utilize a powder comprising particles of a magneticmaterial. When a current is applied, the particles line up and cause thepowder to expand. Rheologic fluid brakes utilize a fluid that changesviscosity when a current is applied. A magnetic brake generates amagnetic field, and when a piece of metal passes through the magneticfield, an anti-current is generated, causing a resistance to movement ofthe metal.

Referring now to the drawings in which like numerals indicate likeelements throughout the several figures, FIG. 1 illustrates amanipulandum in the form of a device 100 incorporating one embodiment ofthe present invention. Trackball devices, such as trackball user inputdevices, may provide a user with the ability to roll asubstantially-spherical manipulandum to guide an indicator (such as acursor) on a user interface device (such as a computer monitor). Thedevice 100 may comprise, for example, a pointing device configured to beused in communication with a device comprising a processor (such as apersonal computer). In other embodiments, the device 100 may beintegrated into a device comprising a processor (such as a laptopcomputer, an electronic book reader, a PDA, a mobile telephone, or anysuch suitable device).

The device 100 shown comprises a substantially-spherical manipulandum102 that can be formed of plastic by injection molding. In otherembodiments, the substantially-spherical manipulandum 102 may be formedof a different material (such as a metal), and/or may be formed by adifferent process (for example, by CNC-machining or die-casting). Thesubstantially-spherical manipulandum 102 may be used to control themovement of an indicator (such as a cursor, an arrow, a highlightedfield, etc.) on a user interface (such as a CRT, an LCD, a plasmascreen, or a projector).

The device 100 shown further comprises four button manipulandum 104 a-d.The button manipulandum 104 a-d may each be configured to provide adifferent signal to a processor in communication with the device 100.For example, in one embodiment, button manipulandum 104 a may beconfigured to provide a user of the device 100 with a one-step means ofreturning to his or her browser's preprogrammed homepage, whilemanipulandum 104 b may be configured to provide the user with a one-stepmeans of navigating to a web search engine page, and manipulandum 104 cmay be configured to allow the user to select an item that he or she hashovered over with an indicator on a user interface device. In otherembodiments, the device 100 may comprise greater or fewer buttonmanipulandum 104 a-d, may comprise no additional manipulandum beyond thesubstantially-spherical manipulandum 102, or may comprise a plurality ofsubstantially-spherical manipulandum.

The device 100 shown in FIG. 1 further comprises an upper housingportion 106 and a housing base 108 that together form a housing for thedevice 100. Some or all of the elements of the embodiment shown in FIGS.1-4 may be housed in a housing. In other embodiments, the device 100 maybe assembled without such a housing, or the housing may house greater orfewer of the device's elements. The upper housing portion 106 and thehousing base 108 may be fashioned from a wide variety of suitablematerials, and may be fashioned from the same or different materials.For example, in one embodiment, the upper housing portion 106 and thehousing base 108 may both be fashioned from a non-magnetic material,such as a plastic, to avoid interference with operation of anelectromagnetic or a magnetic resistive actuator housed within thehousing. In other embodiments, the upper housing portion 106 and/or thehousing base 108 may be fashioned from other materials, such as amagnetic material.

The housing base 108 may be fixably fastened to a surface or otherwisemechanically grounded using any conventional method of fastening, suchas by using adhesives, screws, or collet-pins. The housing base 108shown is configured to secure and prevent movement of the upper housingportion 106 with respect to the housing base 108, and to restrict themovement of the substantially-spherical manipulandum 102. The upperhousing portion 106 shown is configured to expose approximately 37% ofthe surface area of the substantially-spherical manipulandum 102, and tokeep the substantially-spherical manipulandum 102 from escaping thehousing while still permitting enough surface area of thesubstantially-spherical manipulandum 102 for a user of the device 100 toroll and rotate the substantially-spherical manipulandum 102. In otherembodiments, the upper housing portion 106 may expose a greater or alesser percentage of the substantially-spherical manipulandum's 102surface area.

The housing base 108 shown is configured to receive a plurality of jewelbearings (examples of the jewel bearings are shown in FIGS. 2 and 4).The jewel bearings may be configured to substantially hold thesubstantially-spherical manipulandum 102 in place, while simultaneouslyproviding a surface on which the substantially-spherical manipulandum102 may rotate, pivot, and/or swivel with relatively low friction. Thejewel bearings may comprise, for example, fixed steel ball bearings, andmay be configured to contact and position the substantially-sphericalmanipulandum 102 while providing minimal friction when thesubstantially-spherical manipulandum 102 is moved. In other embodiments,the substantially-spherical manipulandum 102 may be held in place and/orsupported by a different suitable means, such as by the use of ballbearings configured to roll when a user of the device 100 rolls thesubstantially-spherical manipulandum 102.

Referring now to FIG. 2, a cutaway elevation view of a sub-assembly 103of the device 100 is shown, according to an embodiment of the presentinvention. The sub-assembly 103 comprises a first actuator 110 and asecond actuator 122, both in communication with the manipulandum 102according to the embodiment shown in FIG. 1 is shown. In the embodimentshown in FIG. 2, a sub-assembly 103 of the device 100 is shown with theupper housing portion 106 that is shown in FIG. 1 removed. Thesubstantially-spherical manipulandum 102 shown may comprise, forexample, an injection-molded plastic trackball. Thesubstantially-spherical manipulandum 102 is in contact with a jewelbearing 150. The jewel bearing 150 shown is configured to position thesubstantially-spherical manipulandum 102 while providing asubstantially-low friction interface between the two elements. In otherembodiments, a plurality of jewel bearings may be used to positionand/or support the substantially-spherical manipulandum 102 whileproviding an ease of manipulability to the substantially-sphericalmanipulandum 102.

In the embodiment shown in FIG. 2, both the first actuator 110 and thesecond actuator 122 shown comprise DC electric motors in communicationwith a processor device, and are both mechanically-grounded to thehousing base 108. In other embodiments, the first and/or the secondactuator may comprise other types of active actuators, and/or resistiveactuators, such as brakes. For example, in one embodiment, the actuator122 may comprise an electromagnetic, magnetic particle,magnetorheologic, electrorheologic, magnetic, or piezo-electric brake.In yet another embodiment, the sub-assembly 103 may comprise only asingle actuator. For example, in one such embodiment, the sub-assembly103 may comprise only the first actuator 110 configured to pivotablyapply a processor-controlled force to the substantially-sphericalmanipulandum 102 with a brake pad contacting surface. In one suchembodiment, pivotably applying the processor-controlled force maycomprise pivotably applying a processor-controlled forcesubstantially-normal to a surface of the substantially-sphericalmanipulandum 102.

Embodiments of the present invention may utilize various other activeand/or resistive actuators as well. For example, in one embodiment, anactive actuator may provide resistive effects. In such an embodiment, amotor in communication with a manipulandum may be short-circuited or setup to act as a generator, causing a resistance. In an embodiment inwhich a motor is set up as a generator, the motor can generate currentback to a power supply during certain braking effects and during dampingeffects.

Other embodiments of the present invention may utilize a piezo-electricactuator. In a piezo-electric actuator, a voltage may be applied to apiezo-ceramic, causing the crystals to elongate and thereby changing theshape of the material. A material shape change of a piezo-ceramic may berelatively small and some type of amplification may be utilized toprovide a mechanical force.

One embodiment of the present invention may comprise a controller (notshown), such as a processor, that may control the application of currentgenerated by a power supply (not shown) to the first and/or secondactuators 110, 122 shown in FIG. 2. In this way, the processor maycontrol the application of forces to the substantially-sphericalmanipulandum 102. Processors can comprise, for example, digital logicalprocessors capable of processing input, executing algorithms, andgenerating output as necessary to create the desired tactile sensationsin the input device in response to an input received from an inputdevice. Such controllers may comprise a microprocessor, an ApplicationSpecific Integrated Circuit (ASIC), and state machines.

Such processors may comprise, or may be in communication with, media,for example computer readable media, that may store instructions that,when executed by the processor, can cause the processor to perform thesteps described herein as carried out, or assisted, by a processor.Embodiments of computer-readable media may comprise, but are not limitedto, an electronic, optical, magnetic, or other storage or transmissiondevice capable of providing a processor, such as the processor in a webserver, with computer-readable instructions. Other examples of mediacomprise, but are not limited to, a floppy disk, CD-ROM, magnetic disk,memory chip, ROM, RAM, ASIC, configured processor, all optical media,all magnetic tape or other magnetic media, or any other medium fromwhich a computer processor can read. Also, various other forms ofcomputer-readable media may transmit or carry instructions to acomputer, such as a router, private or public network, or othertransmission device or channel. The processor, and the processing,described may be in one or more structures, and may be dispersed throughone or more structures.

A controller according to the present invention may be capable ofcontrolling the application of a wide variety of forces to thesubstantially-spherical manipulandum 102, thereby generating acorresponding variety of haptic effects. For example, a controller maycreate effects, such as detents, between entries in a spreadsheetdatabase application. The controller may create additional effects aswell, comprising, for example, bumps, vibrations and stops by applyingvarious currents to the first and/or second actuators 110, 122. In oneembodiment, such a processor may be able to apply to thesubstantially-spherical manipulandum 102 a large processor-controlledforce generated by a first sub-assembly 103 x (shown in FIG. 3), whilesimultaneously applying no forces to the substantially-sphericalmanipulandum 102 with a second sub-assembly 103 y (also shown in FIG.3).

Referring still to FIG. 2, the first actuator 110 shown is configured togenerate a first processor-controlled force that may be applied to thesubstantially-spherical manipulandum 102. The first actuator 110comprises a drive shaft 112 in direct communication with the center of acrank 114. When the first actuator 110 turns the drive shaft 112, thecrank 114 turns with the drive shaft 112. The opposing end of the crank114 is in communication with a link 116 near the circumference of thecrank 114. The link 116 shown is fashioned from a plastic by injectionmolding. As shown in Figure 2, the link 116 is configured to avoidmechanical interference with the second actuator 122 and thesubstantially-spherical manipulandum 102.

The opposing end of the link 116 is in rotatable communication with alever arm 118. The lever arm 118 is fashioned from a plastic byinjection molding. In other embodiments, the lever arm 118 may befashioned from other materials (such as a metal or a wood), and/or byusing a different means of fabrication (such as CNC machining, forging,or die casting). The lever arm 118 is configured to pivot about afulcrum 119. The lever arm 118 is pivotably coupled to the housing base108 at the fulcrum 119. The lever arm 118 is configured to apply theprocessor-controlled force generated by the first actuator 110 to thesubstantially-spherical manipulandum 102 to provide a haptic effect tothe user of the device 100.

The opposing end of the lever arm 118 is rotatably coupled to roller120. The roller 120 comprises a contacting surface, and is configured tocontact the substantially-spherical manipulandum 102. In the embodimentshown, the portion of the roller 120 that contacts thesubstantially-spherical manipulandum 102 comprises neoprene. In otherembodiments, at least a portion of the roller 120 may be fashioned fromother materials (such as, for example, from a plastic, a rubber, ametal, or a wood). In the embodiment shown in FIG. 2, the lever arm 118is configured to apply the first processor-controlled force to thesubstantially-spherical manipulandum 102 via the roller 120. In theembodiment shown, the first actuator 110 is further configured topivotably adjust the amount of force applied to the roller 120.Similarly, the first actuator 110 may be configured to remove the roller120 from contact with the surface of the substantially-sphericalmanipulandum 102 by driving the crank shaft 112 counter-clockwise asviewed in FIG. 2, thereby pivoting the lever arm 118 away from thesubstantially-spherical manipulandum 102.

The second actuator 122 shown in FIG. 2 is configured to generate asecond processor-controlled force. The second processor-controlled forcegenerated by the second actuator 122 may comprise a first componentnormal to the surface of the substantially-spherical manipulandum 102,and a second component tangential to the surface of thesubstantially-spherical manipulandum 102. For example, in oneembodiment, the second processor-controlled force may be directedsubstantially tangential to the surface of the substantially-sphericalmanipulandum 102. The second processor-controlled force generated by thesecond actuator 122 may be transmitted to the roller 120 in theembodiment shown via a transmitting gear 124. In other embodiments thatcomprise a second actuator configured to generate a secondprocessor-controlled force, the generated force may be directlytransmitted by the second actuator to a contacting surface. For example,in one such embodiment, the second actuator 124 may comprise a driveshaft that may be coupled directly to the roller 120.

The roller 120 shown in FIG. 2 is configured to apply the secondprocessor-controlled force to the surface of the substantially-sphericalmanipulandum 102. For example, the second processor-controlled forceapplied to the substantially-spherical manipulandum 102 in theembodiment shown in FIG. 2 may be applied to the surface of thesubstantially-spherical manipulandum 102 in a direction substantiallyperpendicular to the housing base 108. For example, if the roller 120 isturned clockwise as viewed in FIG. 2, the roller 120 may apply a secondprocessor-controlled force substantially perpendicular to the base ofthe housing base 108, in a generally upward direction. If no other forceis presently acting on the substantially-spherical manipulandum 102, thesubstantially-spherical manipulandum 102 may be turned counter-clockwise(as viewed in FIG. 2) in response to the second processor-controlledforce applied by the roller 120. If a user attempts to turn thesubstantially-spherical manipulandum 102 clockwise while the roller 120is applying this example second processor-controlled force, the userwill encounter a resistance to the attempted movement.

In one embodiment, the second processor-controlled force applied to thesubstantially-spherical manipulandum 102 may be associated with thepivotably-applied, first processor-controlled force applied to thesubstantially-spherical manipulandum 102. For example, for asubstantially similar amount of force generated by the second actuator122, the second processor-controlled force applied to thesubstantially-spherical manipulandum 102 may increase as asubstantially-normal, first processor-controlled force pivotably appliedto the substantially-spherical manipulandum 102 increases. Thesubstantially-normal, first processor-controlled force may comprise aforce generated by the first actuator 110, and directed substantiallynormal to and towards the surface of the substantially-sphericalmanipulandum 102. An increase in a tangential component of the secondprocessor-controlled force applied to the substantially-sphericalmanipulandum 102 for a substantially similar amount of force generatedby the second actuator 122 may result from the increase in a frictionforce in substantially the same direction as the tangential component ofthe second processor-controlled force applied by the roller 120. Theincrease in the friction force is a product of the coefficient offriction and the amount of substantially-normal, firstprocessor-controlled force pivotably applied by the roller 120.Similarly, if the first actuator 110 operates to pivot the roller 120away from contact with the substantially-spherical manipulandum 102, thesecond processor-controlled force generated by the second actuator 122may not be applied to the substantially-spherical manipulandum, as theremay be no friction force between the roller 120 and thesubstantially-spherical manipulandum 102.

Contact between the roller 120 and the substantially-sphericalmanipulandum 102 may cause a resistance to movement of thesubstantially-spherical manipulandum 102. For example, a secondprocessor-controlled force directed substantially perpendicular to andtoward the base of the housing base 108 cause a resistance to acounter-clockwise rotation of the substantially-spherical manipulandum102 as viewed in FIG. 2. If the substantially-spherical manipulandum 102is turning counter-clockwise at the time of such contact, the resistancemay cause the substantially-spherical manipulandum 102 to stop turning.In one embodiment, the resistance to the movement may be low enough suchthat the user can overcome the resistance. When the first and/or secondactuators 110, 122 receive a pulsed current, a haptic effect in the formof a vibration, step, and/or bump may be created.

Referring now to FIG. 3, a plan view of the device 100 is shownillustrating an example layout of a device comprising a plurality ofsub-assemblies 103 x, 103 y, both in communication with thesubstantially-spherical manipulandum 102. The first and secondsub-assemblies 103 x, 103 y are both pivotably coupled to the housingbase 108 shown. The first sub-assembly 103 x shown is configured toprovide haptic effects to an X-axis of the device 100, while the secondsub-assembly 103 y is configured to provide haptic effects to a Y-axisof the device 100, where the Y-axis is substantially orthogonal to theX-axis. The sub-assemblies 103 x, 103 y shown do not illustrate everyelement shown in sub-assembly 103 of FIG. 2, but have been simplified toaid in illustration of their example layout in this embodiment. In otherembodiments, the device 100 may comprise greater or fewer numbers ofsub-assemblies, and a device comprising a plurality of suchsub-assemblies may have the sub-assemblies arranged in such a fashionthat they are substantially not orthogonal to one another.

The sub-assemblies 103 x, 103 y shown each comprise a lever arm 118 x,118 y, a roller 120 x, 120 y, a second actuator 122 x, 122 y, atransmitting gear 124 x, 124 y. The sub-assemblies 103 x, 103 y shownfurther comprise the other elements shown with respect to FIG. 2. Thesub-assemblies 103 x, 103 y may act separately or in synchronization toprovide a haptic effect to the substantially-spherical manipulandum 102.

The orthogonal relationship between sub-assemblies 103 x, 103 y shown inFIG. 3 may provide the user with a variety of haptic effects that may beimplemented with respect to a two-dimensional user interface device. Forexample, a television remote control employing a trackball devicecomprising the orthogonal arrangement of sub-assemblies 103 x, 103 yshown in FIG. 3 may be able to provide haptic effects to the user of thedevice 100 that correspond to the location of images of objects on atwo-dimensional graphical user interface device (such as a plasma screentelevision).

Referring now to FIG. 4, a close-up perspective view of an embodiment ofthe present invention comprising a sensing device 136 y is shown. Thedevice 100 shown comprises the two sub-assemblies 103 x, 103 y shown inFIG. 3. The sub-assembly 103 x comprises a link 116 x rotatably coupledto the lever arm 118 x, which is pivotably coupled to the housing base108. The sub-assembly 103 x further comprises the second actuator 122 x.The second actuator 122 x shown comprises a drive shaft 128 x. Thesecond actuator 122 x is configured to drive the drive shaft 128 x. Thedrive shaft 128 x is fixably coupled to both a drive gear 130 x, and adrive pulley 132 x. The drive shaft 128 x is configured tosimultaneously drive the drive gear 130 x and the drive pulley 132 x.The drive gear 130 x is configured to drive the transmission gear 124 x,which his configured to drive a roller gear 126 x in communication witha roller 120 x contacting surface.

The drive pulley 132 x is in communication with a drive belt 134 x. Thedrive belt 134 x is also in communication with an encoder drive 136 x.The drive pulley 132 x is configured to drive the encoder drive 136 x.The encoder drive 136 x is configured to receive an encoder disk, suchas the encoder disk 138 y shown with respect to sub-assembly 103 y inFIG. 4. Sub-assembly 103 y comprises analogous elements to those ofsub-assembly 103 x, some of which are hidden from view by the encoderdisk 138 y. For example, as shown by FIG. 4, sub-assembly 103 ycomprises a transmission gear 124 y in communication with a drive gear(not shown) that is in communication with a drive shaft (not shown) ofthe second actuator 122 y (as shown in FIG. 3). The sub-assembly 103 yfurther comprises a roller gear 126 y in communication with thetransmission gear 124 y, a roller 120 y in communication with the rollergear 126 y and the substantially-spherical manipulandum 102, a lever arm118 y, and a drive pulley 132 y in communication with an encoder drive136 y.

The encoder disk 138 y is fixably coupled to the encoder drive 136 y,and is configured be driven by the second actuator 122 y (shown in FIG.3). The encoder disk 138 y may comprise coding (not shown) from which asensing device 140 y may sense the movement of the encoder disk 138 ywith respect to the sensing device 140 y. As such, the sensing device140 y is in direct communication with the second actuator 122 y, androller 120 y, and in indirect communication with thesubstantially-spherical manipulandum 102 via the roller 120 y.

The coding on the encoder disk 138 y may comprise, for example, a seriesof light and dark markings capable of being distinguished by an opticalsensor. In other embodiments, the coding may comprise other types andconfigurations, such as one or more symbols, markings, etchings, holes,depressions, material additions, magnetized strips, or any other type ofidentifier that may help convey the relative movement or location of theencoder disk 138 y with respect to the sensing device 140 y, and/or therelative movement or location of the roller 120 y, the actuator 122 y,or the substantially-spherical manipulandum 102 with respect to thesensing device 140 y and/or with respect to one another.

The coding may be provided using a variety of different processes, forexample, the coding may be deposited on, drawn on, ground into, meltedinto, or affixed to the encoder disk 138 y. In another embodiment, theroller 120 y, and/or the substantially-spherical manipulandum 102 maycomprise the coding, and the sensing device 140 y may be alternatelyconfigured to sense coding on an element of sub-assembly 103 y otherthan encoder disk 138 y. In yet another embodiment, a single sensingdevice may be configured to simultaneously sense a movement of at leastone element of both assemblies 103 x, 103 y.

The sensing device 140 y shown in FIG. 4 comprises a sensor configuredto sense the coding of the encoder disk 138 y. The sensing device 140 yis thusly configured to sense a movement of the encoder disk 138 y withrespect to the sensing device 140 y. The sensor may comprise, forexample, an optical sensor capable of sensing light and dark markings,such as a series of markings that comprise an example coding. In otherembodiments that comprise a sensing device, the sensing device 140 y maycomprise a sensor configured to sense a different type of coding, suchas magnetic information, an etching, a material addition, etc. Inanother embodiment, the sensing device 140 y may be capable of sensing,for example, a relative movement between the substantially-sphericalmanipulandum 102 and the roller 120 y, and/or the relative movementbetween the substantially-spherical manipulandum 102 or the roller 120 yand the sensing device 140 y.

The sensing device 140 y may communicate to a processor device incommunication with at least one of the first and second assemblies 103x, 103 y the relative movement between the encoder disk 138 y and thesensing device 140 y in a sensor output signal. From the sensor outputsignal, the processor device may be able to ascertain a movement of orthe position of the substantially-spherical manipulandum 102. Theprocessor device may be in communication with an I/O port connected to apower supply (not shown). In response to receiving the sensor outputsignal from the sensing device 140 y, the processor device may send afeedback control signal in the form of an electrical current generatedby a power supply (such as a battery, an alternating current, or adirect current) to the first and/or second actuators 110 y, 122 y of thesub-assembly 103 y, and/or the first and/or second actuators 110 x, 122x of the first sub-assembly 103 x to create a desired haptic effect.

Referring still to FIG. 4, a jewel bearing 150 is shown supporting thesubstantially-spherical manipulandum 102. The jewel bearing 150 shown isconfigured to support the substantially-spherical manipulandum 102 whileproviding a substantially-low friction interface between the twoelements. In other embodiments, a plurality of jewel bearings may beused to support and/or position the substantially-spherical manipulandum102 while providing an ease of manipulability to thesubstantially-spherical manipulandum 102.

Various methods, systems, and devices utilizing embodiments of thepresent invention may be employed. For example, in one embodiment, adevice may comprise a housing, a substantially-spherical manipulandum,and a lever arm pivotably coupled to the housing. Thesubstantially-spherical manipulandum may comprise a trackball, such asan injection-molded plastic sphere commonly used in trackball pointingdevices. A user of the device may use the substantially-sphericalmanipulandum to communicate with the device. For instance, the user mayscroll through a list of contacts on a PDA device using a trackballmanipulandum by rolling the trackball. The lever arm may be configuredto apply a processor-controlled force to the substantially-sphericalmanipulandum to provide a haptic effect. For example, in one embodiment,a first actuator in communication with the lever arm may be configuredto generate the processor-controlled force. The processor-controlledforce may comprise a substantially-normal, processor-controlled force(such as a force directed substantially-normal to a surface of thesubstantially-spherical manipulandum). Such a device may be capable ofproducing a wide variety of haptic effects, comprising bumps, stops, andvibrations.

In one embodiment, the haptic effect provided may comprise apredetermined haptic effect. The haptic effect provided may comprise,for example, a predetermined haptic effect, and a processor maydetermine the haptic effect provided by using a look-up table of hapticeffects. In another embodiment where the haptic effect providedcomprises a predetermined haptic effect, a processor may receive aninput signal, and use an algorithm to determine which haptic effect toprovide in response.

A contacting surface, such as a brake pad or a roller, may be coupled tothe lever arm in communication with the substantially-sphericalmanipulandum. For example, in one embodiment, a roller comprising aneoprene contacting surface configured to contact a plasticsubstantially-spherical manipulandum may be rotatably coupled to thelever arm. The roller in such an embodiment may be configured to apply asecond processor-controlled force to the substantially-sphericalmanipulandum. The second processor-controlled force may comprise a firstcomponent directed normal to a surface of the substantially-sphericalmanipulandum and a second component directed tangential to the surfaceof the substantially-spherical manipulandum. For example, in oneembodiment, the second processor-controlled force may comprise a forcedirected substantially tangential to the surface of thesubstantially-spherical manipulandum. The second processor-controlledforce may be associated with the first processor-controlled forcegenerated by the first actuator in communication with the lever arm. Asecond actuator in communication with the roller may be configured togenerate the second processor-controlled force. In one embodimentemploying a roller, the lever arm may be configured to apply the firstprocessor-controlled force to the substantially-spherical manipulandumvia the roller.

The contacting surface may comprise a material having a coefficient offriction such that when the contacting surface is brought into contactwith a substantially-spherical manipulandum with a firstprocessor-controlled force applied by a first actuator, the firstprocessor-controlled force, and/or a second processor-controlled forceprovided by a second actuator may slow or stop movement between thecontacting surface and the substantially-spherical manipulandum. In oneembodiment, an interface disposed between a roller contacting surfaceand the substantially-spherical manipulandum may comprise apredetermined static and/or kinetic coefficient of friction. In such anembodiment, the second processor-controlled force may be associated withthe predetermined coefficient of friction. For example, in oneembodiment, the second processor-controlled force may vary, at least inpart, with the predetermined coefficient of friction.

The haptic effect provided to the user of the trackball device may varyaccording to the second processor-controlled force. For example, as thesecond processor-controlled force increases, resistance to a movement ofthe substantially-spherical manipulandum 102 in a direction opposing thesecond processor-controlled force may increase, alerting the user to thepresence of an obstacle (such as an object, a file, a screen boundary,etc.).

In one embodiment, the second processor-controlled force may beassociated with the first processor-controlled force. For example, inone embodiment, the first actuator configured to generate the firstprocessor-controlled force may be slaved to the second actuatorconfigured to generate the second processor-controlled force. In onesuch embodiment, when the second actuator is actuated by a processor andgenerates the second processor-controlled force, the slaved firstactuator may generate a predetermined first processor-controlled forceassociated with the particular second processor-controlled forcegenerated by the second actuator. In one such embodiment, the firstactuator may be in direct or indirect communication with the processordevice, and may be actuated only when the second actuator is actuated.In one such embodiment, the first processor-controlled force may becontrolled directly or indirectly by the processor via the secondactuator.

Another apparatus according to the present invention may comprise afirst actuator configured to pivotably provide a processor-controlledforce to a contacting surface (such as a roller) in communication with asubstantially-spherical manipulandum (such as a trackball) to provide ahaptic effect. For example, in one such embodiment, the first actuatormay be mechanically grounded to a housing base, with a drive shaftextending substantially perpendicular to, and away from, the housingbase. In such an embodiment, a crank may be coupled to the firstactuator's drive shaft, and the contacting surface (such as a roller)may be coupled to the crank. In such an embodiment, the first actuatormay be configured to pivot the crank, and the contacting surface thereontoward and away from the substantially-spherical manipulandum along apath substantially parallel to the housing base. A second actuator incommunication with the contacting surface may also be coupled to thecrank, and may be configured to provide a second processor-controlledforce to the substantially-spherical manipulandum.

In one embodiment, the processor-controlled force provided by the firstactuator may comprise, for example, a substantially-normal,processor-controlled force. In one such embodiment, the contactingsurface may be configured to communicate the processor-controlled. forceto the substantially-spherical manipulandum. One such embodiment mayfurther comprise a second actuator. The second actuator may beconfigured to provide a second processor-controlled force to thecontacting surface. The second processor-controlled force may beassociated with the first processor-controlled force provided by thefirst actuator.

In one embodiment, a lever may be disposed between the first actuatorand the contacting surface. The lever may pivot about amechanically-grounded fulcrum. In one such embodiment, the firstactuator may be configured to pivotably provide the firstprocessor-controlled force to the contacting surface via the lever. Thelever may further be configured to provide pivotable communicationbetween the contacting surface and the substantially-sphericalmanipulandum.

One embodiment of the present invention may further comprise a sensingdevice. The sensing device may be in communication with thesubstantially-spherical manipulandum, the lever arm, a contactingsurface (such as a roller), a first actuator configured to generate thefirst processor-controlled force, and/or a second actuator configured togenerate the second processor-controlled force. Likewise, the sensingdevice may be configured to sense a movement of thesubstantially-spherical manipulandum, the lever arm, the roller, thefirst actuator, and/or the second actuator.

One such device may comprise a processor in communication with thesensing device and the first actuator and/or the second actuator. Theprocessor may be configured to control the generation of the firstprocessor-controlled force and/or the second processor-controlled force.The processor may be configured to provide haptic feedback. Theprocessor may receive a sensor output signal from the sensing device.For instance, a sensor output signal may comprise information about therelative movement between the substantially-spherical manipulandum andthe sensing device, the relative movement between thesubstantially-spherical manipulandum and the contacting surface, therelative movement between the contacting surface and the sensing device,and/or the position of the substantially-spherical manipulandum. Theprocessor may send a feedback control signal to the first and/or secondactuators in response to the sensor output signal. For instance, thefeedback control signal may comprise an electrical current. Theprocessor may be in communication with an I/O port and a power supply.

The present invention may also be embodied in various methods. Forexample, in one method according to the present invention, a firstprocessor-controlled force may be pivotably applied to asubstantially-spherical manipulandum (such as a trackball) to provide ahaptic effect. In one embodiment, pivotably applying the firstprocessor-controlled force to the substantially-spherical manipulandummay comprise pivotably applying a substantially-normal,processor-controlled force to a substantially-spherical manipulandum ina direction substantially normal to the surface of thesubstantially-spherical manipulandum. In another embodiment, pivotablyapplying the first processor-controlled force to thesubstantially-spherical manipulandum may comprise applying a pivotingforce to a lever arm configured to apply the first processor-controlledforce to the substantially-spherical manipulandum. Theprocessor-controlled force may be generated in one embodiment with anactive actuator (such as a DC motor), and/or with a passive actuator(such as an electromagnetic brake).

This method may further comprise applying a second processor-controlledforce to the substantially-spherical manipulandum in a directionsubstantially tangential to the surface of the substantially-sphericalmanipulandum to provide an additional haptic effect, and/or enhance thehaptic effect provided by the first processor-controlled force pivotablyapplied to the substantially spherical manipulandum. The secondprocessor-controlled force applied to the substantially-sphericalmanipulandum may be associated with the pivotably applied firstprocessor-controlled force. For example, in one embodiment, the secondprocessor-controlled force may vary, at least in part, with the firstprocessor-controlled force. In another embodiment, the firstprocessor-controlled force may be slaved to the secondprocessor-controlled force. In yet another embodiment, the secondprocessor-controlled force applied to the substantially-sphericalmanipulandum may be associated with a force associated with thesubstantially-spherical manipulandum, such as the weight of thesubstantially-spherical manipulandum, or a force provided by the user ofthe substantially-spherical manipulandum.

The second processor-controlled force may be generated in one embodimentwith an active actuator (such as a DC motor), and/or with a passiveactuator (such as an electromagnetic brake). In one embodiment, applyingthe second processor-controlled force to the substantially-sphericalmanipulandum may comprise applying a second processor-controlled forceto a roller rotatably coupled to a lever arm configured to apply thesecond processor-controlled force to the substantially-sphericalmanipulandum.

Another method according to the present invention may comprise pivotablyapplying a first processor-controlled force to a contacting surface(such as a roller) in communication with a substantially-sphericalmanipulandum to provide a haptic effect. In one such embodiment,pivotably applying the first processor-controlled force to thecontacting surface may comprise applying a pivoting force to a lever incommunication with the contacting surface.

One embodiment of this method may further comprise applying a secondprocessor-controlled force to the contacting surface. The secondprocessor-controlled force may comprise, for example, a first componentnormal to the surface of the substantially-spherical manipulandum and asecond component tangential to the surface of thesubstantially-spherical manipulandum. In one such embodiment, the secondprocessor-controlled force may be associated with the pivotably-applied,first processor-controlled force. For example, in one embodiment, thesecond processor-controlled force may vary, at least in part, with thefirst processor-controlled force. In another such embodiment, the secondprocessor-controlled force may be associated with a force associatedwith the substantially-spherical manipulandum, such as the weight of thesubstantially-spherical manipulandum, or a force provided to thesubstantially-spherical manipulandum by a user of thesubstantially-spherical manipulandum. The first processor-controlledforce may comprise, for example, a substantially-normal,processor-controlled force in one method according to the presentinvention.

In one method according to the present invention, a sensing device maysense a movement of a substantially-spherical manipulandum, a contactingsurface, a lever arm, a roller, a first actuator, and/or a secondactuator. In one such method, the first processor-controlled forceand/or the second processor-controlled force may be varied in responseto a movement sensed by the sensing device. An element of a deviceaccording to the present invention may comprise a coding. For example,in one embodiment, a roller contacting surface may comprise the coding.In another embodiment, the coding may be marked on an encoder disk incommunication with an actuator. In one embodiment, a sensing device maysense a movement of the substantially-spherical manipulandum by sensinga coding etched on an exterior surface of the substantially-sphericalmanipulandum.

The coding may comprise information from which the sensing device may becapable of sensing the relative movement between thesubstantially-spherical manipulandum, the contacting surface, the firstactuator, the second actuator, or the lever arm and the sensing device.The coding may additionally or alternatively comprise information fromwhich the sensing device may be capable of sensing the position of thesubstantially-spherical manipulandum, the first actuator, and/or thesecond actuator. For example, in one embodiment, the coding may comprisea series of markings printed on the substantially-spherical manipulandumand visible to a sensing device. In another embodiment, a coding maycomprise a series of light and dark markings affixed to a cylindricalroller contacting surface configured to rotatably communicate with thesubstantially-spherical manipulandum. The light and dark markings mayeach be unique, allowing the optical sensor to determine the degree ofrelative rotation of the contacting surface with respect to thestationary sensing device.

The sensing device may be configured to sense the coding. For instance,the sensing device may comprise an optical reader capable of sensinglight and dark markings. The sensing device may be affixed to astationary housing, and may have a substantially unobstructed line ofsight to the coding. For instance, in one embodiment there may not beany physical obstructions between a sensing device comprising an opticalsensor located in the sensing device and a portion of the coding of thesubstantially-spherical manipulandum.

Referring again to the figures, FIG. 5 is a block diagram, illustratingone embodiment of a device 500 according to the present invention. Thedevice 500 may comprise, for example, a trackball pointing device. Inthe embodiment shown, the device 500 comprises a sensing device 540. Thesensing device 540 may comprise one of the sensors discussed in relationto FIG. 4 or various other types of sensors.

The device 500 further comprises a first actuator 510 configured togenerate a first processor-controlled force and a second actuator 522configured to generate a second processor-controlled force. In oneembodiment, the first and second actuators 510, 522 may comprise DCelectric motors. In other embodiments, the first and/or second actuators510, 522 may comprise other types of actuators, such as brakes and ACelectric motors.

The sensing device 540 and the first and second actuators 510, 522 shownare all in communication with a processor 556. The processor 556 mayreceive sensor information in the form of a sensor output signal fromthe sensing device 540, may perform control algorithms, and may providefeedback control signals to the first and/or second actuators 510, 522.

The device shown in FIG. 5 further comprises an input/output (I/O) port560, such as a game port, for performing bi-directional communicationwith external devices utilizing an embodiment of the present invention.In the embodiment shown, the device 500 receives power from an externalpower supply 564. In other embodiments, power may be supplied throughthe I/O port 560 or by utilizing an internal power supply. Variousembodiments may utilize additional components as well, such as anamplifier to amplify signals to the first and/or second actuators 510,522. In one embodiment, the device 500 may comprise two or more sets ofactuators, where at least one actuator in each set is configured togenerate a first processor-controlled force, and at least one otheractuator in each set is configured to generate a secondprocessor-controlled force.

FIG. 6 is a flowchart illustrating a process of navigating email on apersonal computer comprising a processor that is in communication withuser interface device (such as a CRT monitor) and a trackball device(such as a wireless infrared trackball mouse comprising a battery powersupply) utilizing an embodiment of the present invention. The methodillustrated in FIG. 6 is described with reference to the device (100)shown in FIGS. 1-4. The device (100) comprises a substantially-sphericalmanipulandum (102). For example, the substantially-sphericalmanipulandum (102) may comprise a metal ball-bearing trackball. As shownin box 605, the user of the device (100) receives an email. Then, asshown in box 615, the user utilizes an interface device, such as button(104 a), to open the email.

Using the substantially-spherical manipulandum (102), the user may then,as shown in box 625, scroll to the bottom of the email displayed on theuser interface device (such as an LCD computer monitor) by rolling thesubstantially-spherical manipulandum (102) in the appropriate direction.A sensing device (140 y) may then sense a coding on an encoder disk (138y) in direct or indirect communication with the substantially-sphericalmanipulandum (102) as described with respect to FIG. 4. From the coding,the sensing device (140 y) may be able to ascertain, for example, therelative movement of the encoder disk (138 y) in direct communicationwith a first actuator (110) and or a second actuator (122 y) withrespect to the sensing device (140 y) and therefrom the relativemovement or position of the substantially-spherical manipulandum (102).The sensing device (140 y) may then send the sensed information in asensing device output signal to the processor of the personal computerdevice the user is using to run an email viewing application.

The user interface device in communication with the personal computermay or may not be large enough to display the received email. Theprocessor may then be able to determine whether the email message islonger than the visible portion of the user interface device as shown inbox 635. If the email is longer than the visible portion of the screen,the processor that received the sensing device (140 y) output signal maycommunicate with the first and/or second actuators (110, 122) asdescribed with respect to FIGS. 2-4 by sending a feedback controlsignal. The feedback control signal may comprise an electric currentsupplied by a power supply to the first and/or second actuators (110,122).

The first and/or second actuators (110, 122) may then receive thefeedback control signal sent by the processor and, as shown in box 645,may cause a detent effect on the substantially-spherical manipulandum(102) by causing contact between a contacting surface such as a roller(120) and the substantially-spherical manipulandum (102). For example,the first actuator (110) may pivotably force the roller (120) towardsthe substantially-spherical manipulandum (102) with a lightsubstantially-normal, first processor-controlled force while the secondactuator (122) simultaneously applies a second processor-controlledforce to the substantially-spherical manipulandum (102) by turning theroller (120). The contact between the roller (120) contacting surfaceand the substantially-spherical manipulandum (102) may create aresistance to the movement of the substantially-spherical manipulandum(102) in communication with the substantially-spherical manipulandum(102) over a short interval of time to create the detent effect. Theuser can overcome the detent haptic effect by continuing to scroll downthrough the email by turning the substantially-spherical manipulandum(102). The detent effect may provide an indicator to the user that he orshe is scrolling beyond the visible portion of the email message. In oneembodiment, the first actuator (110) may be slaved to the secondactuator (122), and may be actuated whenever the second actuator (122)receives a feedback control signal from the processor.

Referring still to FIG. 6, if the email is not longer than the visibleportion of the user interface device, the processor may send a differentfeedback control signal to the first and/or second actuators (110, 122)such as by supplying a stronger electric current. The feedback controlsignal may cause, for example, the first actuator (110) to generate astronger substantially-normal, first processor-controlled force than isprovided to create the detent effect in order to provide such a greatnormal force that the friction force applied to thesubstantially-spherical manipulandum (102) by the contacting surfaceroller (120) comprises a tangential force so great that thesubstantially-spherical manipulandum (102) cannot substantially be movedwith respect to the roller (120). As shown in box 655, this contact maycause a stop effect in the device (100), comprising a strong resistanceto further movement of the substantially-spherical manipulandum (102) bythe user. Once the effect has been provided, the process ends as shownby box 665.

Various other types of effects may be utilized. For example, in oneembodiment, the actuator may provide a “bump” when the end of the emailis reached. If the user continues to scroll past the bump, theapplication may display the next email in the folder the user iscurrently viewing. In one embodiment, the second actuator (122) may beconfigured to apply a downhill effect by turning thesubstantially-spherical manipulandum (102) faster in the same directionthat the user may be presently turning the substantially-sphericalmanipulandum (102).

Embodiments of the present invention may be utilized by a broad array ofdevices, including, without limitation, remote controls, pointingdevices, editing devices, drawing devices, devices developed forvisually-impaired users, cell phones, personal digital assistants,cameras, camcorders, MP3 players, and other electronic devices. Forexample, a cell phone may incorporate a trackball device according tothis invention for use in navigating a menu structure. A televisionremote control may also incorporate an embodiment of the presentinvention for channel navigation, volume control, and other relatedfunctions. Similarly, an audio component remote control may utilize anembodiment for volume control or other audio control. A laptop computermay utilize an embodiment for navigation, volume control, or any otherfunction utilizing a trackball or any other substantially-sphericalmanipulandum user interface device. PDA's, handheld navigation, andhandheld email appliances may also benefit from utilizing an embodimentof the present invention.

A camera may utilize an embodiment of the present invention for usercontrol of the focus, f-stop, menu navigation, and other camera-relatedfunctions. Since the effects provided by the actuator may beprogrammable, one manipulandum may be utilized to perform many or all ofthe functions on the camera. A video recorder may utilize an embodimentof the present invention to provide functions such as shuttle, fastforward, and reverse. An actuator may create detents on a frame-by-framebasis for the shuttle function and hard stops for fast forward andreverse.

The foregoing description of the embodiments of the invention has beenpresented only for the purpose of illustration and description and isnot intended to be exhaustive or to limit the invention to the preciseforms disclosed. Numerous modifications and adaptations thereof will beapparent to those skilled in the art without departing from the spiritand scope of the present invention.

1. An apparatus comprising: a housing; a substantially-sphericalmanipulandum; a lever arm pivotably coupled to the housing, andconfigured to apply a processor-controlled force to thesubstantially-spherical manipulandum to provide a haptic effect.
 2. Theapparatus of claim 1, wherein the processor-controlled force comprises asubstantially-normal, processor-controlled force, thesubstantially-normal, processor controlled force directed substantiallynormal to a surface of the substantially-spherical manipulandum.
 3. Theapparatus of claim 1, wherein the haptic effect comprises apredetermined haptic effect.
 4. The apparatus of claim 1, wherein theprocessor-controlled force comprises a first processor-controlled force,and further comprising: a roller rotatably coupled to the lever armconfigured to apply a second processor-controlled force to thesubstantially-spherical manipulandum, the second processor-controlledforce being associated with the first processor-controlled force.
 5. Theapparatus of claim 4, wherein the lever arm is configured to apply thefirst processor-controlled force to the substantially-sphericalmanipulandum via the roller.
 6. The apparatus of claim 4, furthercomprising: a first actuator in communication with the lever armconfigured to generate the first processor-controlled force; and asecond actuator in communication with the roller configured to generatethe second processor-controlled force.
 7. The apparatus of claim 6,further comprising: a sensing device in communication with at least oneof the substantially-spherical manipulandum, the lever arm, the roller,the first actuator, and the second actuator.
 8. The apparatus of claim7, wherein the sensing device is configured to sense a movement of atleast one of the substantially-spherical manipulandum, the lever arm,the roller, the first actuator, and the second actuator.
 9. Theapparatus of claim 7, further comprising: a processor in communicationwith the sensing device and at least one of the first actuator and thesecond actuator, wherein the processor is configured to control thegeneration of at least one of the first processor-controlled force andthe second processor-controlled force.
 10. The apparatus of claim 1,wherein the substantially-spherical manipulandum comprises a trackball.11. An apparatus comprising: an actuator configured to pivotably providea processor-controlled force to a contacting surface in communicationwith a substantially-spherical manipulandum to provide a haptic effect.12. The apparatus of claim 11, wherein the processor-controlled forcecomprises a substantially-normal, processor-controlled force, thesubstantially-normal, processor controlled force directed substantiallynormal to a surface of the substantially-spherical manipulandum.
 13. Theapparatus of claim 11, wherein the contacting surface is configured tocommunicate the processor-controlled force to thesubstantially-spherical manipulandum.
 14. The apparatus of claim 11,wherein the contacting surface comprises a roller.
 15. The apparatus ofclaim 11, further comprising a lever disposed between the actuator andthe contacting surface.
 16. The apparatus of claim 15, wherein theactuator is configured to pivotably provide the processor-controlledforce to the contacting surface via the lever.
 17. The apparatus ofclaim 15, wherein the lever is configured to provide pivotablecommunication between the contacting surface and thesubstantially-spherical manipulandum.
 18. The apparatus of claim 11,wherein the actuator comprises a first actuator, theprocessor-controlled force comprises a first processor-controlled force,and further comprising: a second actuator configured to provide a secondprocessor-controlled force to the contacting surface, wherein the secondprocessor-controlled force comprises a first component normal to asurface of the substantially-spherical manipulandum and a secondcomponent tangential to the surface of the substantially-sphericalmanipulandum, and is associated with the first processor-controlledforce.
 19. The apparatus of claim 18, further comprising a sensingdevice in communication with at least one of the substantially-sphericalmanipulandum, the contacting surface, the first actuator, and the secondactuator.
 20. The apparatus of claim 19, wherein the sensing device isconfigured to sense a movement of at least one of thesubstantially-spherical manipulandum, the contacting surface, the firstactuator, and the second actuator.
 21. The apparatus of claim 19,further comprising a processor in communication with the sensing deviceand at least one of the first actuator and the second actuator, whereinthe processor is configured to control the generation of at least one ofthe first processor-controlled force and the second processor-controlledforce.
 22. The apparatus of claim 11, wherein thesubstantially-spherical manipulandum comprises a trackball.
 23. A methodcomprising: pivotably applying a first processor-controlled force to asubstantially-spherical manipulandum to provide a haptic effect; andapplying a second processor-controlled force to thesubstantially-spherical manipulandum to provide the haptic effect,wherein the second processor-controlled force comprises a firstcomponent normal to a surface of the substantially-sphericalmanipulandum and a second component tangential to the surface of thesubstantially-spherical manipulandum.
 24. The method of claim 23,wherein pivotably applying the first processor-controlled forcecomprises pivotably applying a substantially-normal,processor-controlled force, the substantially-normal, processorcontrolled force directed substantially normal to a surface of thesubstantially-spherical manipulandum.
 25. The method of claim 23,wherein the second processor-controlled force is associated with thefirst processor-controlled force.
 26. The method of claim 23, whereinthe second processor-controlled force is associated with a forceassociated with the substantially-spherical manipulandum.
 27. The methodof claim 23, wherein pivotably applying the first processor-controlledforce to the substantially-spherical manipulandum comprises applying apivoting force to a lever arm configured to apply the firstprocessor-controlled force to the substantially-spherical manipulandum.28. The method of claim 27, wherein applying the secondprocessor-controlled force to the substantially-spherical manipulandumcomprises applying the second processor-controlled force to a rollerrotatably coupled to the lever arm configured to apply the secondprocessor-controlled force to the substantially-spherical manipulandum.29. The method of claim 28, further comprising sensing a movement of atleast one of the substantially-spherical manipulandum, the lever arm,and the roller, and varying at least one of the firstprocessor-controlled force and second processor-controlled force inresponse.
 30. The method of claim 23, wherein thesubstantially-spherical manipulandum comprises a trackball.
 31. A methodcomprising: pivotably applying a first processor-controlled force to acontacting surface in communication with a substantially-sphericalmanipulandum to provide a haptic effect; and applying a secondprocessor-controlled force to the contacting surface, wherein the secondprocessor-controlled force comprises a first component normal to asurface of the substantially-spherical manipulandum and a secondcomponent tangential to the surface of the substantially-sphericalmanipulandum.
 32. The method of claim 31, wherein pivotably applying thefirst processor-controlled force comprises pivotably applying asubstantially-normal, processor-controlled force, thesubstantially-normal, processor controlled force directed substantiallynormal to a surface of the substantially-spherical manipulandum.
 33. Themethod of claim 31, wherein the second processor-controlled force isassociated with the first processor-controlled force.
 34. The method ofclaim 31, wherein the second processor-controlled force is associatedwith a force associated with the substantially-spherical manipulandum.35. The method of claim 31, wherein the contacting surface comprises aroller.
 36. The method of claim 31, wherein pivotably applying the firstprocessor-controlled force to the contacting surface comprises applyingthe first processor-controlled force to a lever in communication withthe contacting surface.
 37. The method of claim 31, further comprisingsensing a movement of at least one of the substantially-sphericalmanipulandum and the contacting surface, and varying at least one of thefirst processor-controlled force and the second processor-controlledforce in response.
 38. The method of claim 31, wherein thesubstantially-spherical manipulandum comprises a trackball.
 39. Acomputer-readable medium on which is encoded program code, the programcode comprising: program code for pivotably applying a firstprocessor-controlled force to a substantially-spherical manipulandum toprovide a haptic effect; and program code for applying a secondprocessor-controlled force to the substantially-spherical manipulandumto provide the haptic effect, wherein the second processor-controlledforce comprises a first component normal to a surface of thesubstantially-spherical manipulandum and a second component tangentialto the surface of the substantially-spherical manipulandum.
 40. Thecomputer-readable medium of claim 39, wherein the program code forpivotably applying the first processor-controlled force comprisesprogram code for pivotably applying a substantially-normal,processor-controlled force, the substantially-normal, processorcontrolled force directed substantially normal to a surface of thesubstantially-spherical manipulandum.
 41. The computer-readable mediumof claim 39, wherein the second processor-controlled force is associatedwith the first processor-controlled force.
 42. The computer-readablemedium of claim 39, wherein the second processor-controlled force isassociated with a force associated with the substantially-sphericalmanipulandum.
 43. The computer-readable medium of claim 39, wherein theprogram code for pivotably applying the first processor-controlled forceto the substantially-spherical manipulandum comprises program code forapplying a pivoting force to a lever arm configured to apply the firstprocessor-controlled force to the substantially-spherical manipulandum.44. The computer-readable medium of claim 43, wherein the program codefor applying the second processor-controlled force to thesubstantially-spherical manipulandum comprises program code for applyingthe second processor-controlled force to a roller rotatably coupled tothe lever arm configured to apply the second processor-controlled forceto the substantially-spherical manipulandum.
 45. The computer-readablemedium of claim 44, further comprising program code for sensing amovement of at least one of the substantially-spherical manipulandum,the lever arm, and the roller, and program code for varying at least oneof the first processor-controlled force and second processor-controlledforce in response.
 46. The computer-readable medium of claim 39, whereinthe substantially-spherical manipulandum comprises a trackball.
 47. Acomputer-readable medium on which is encoded program code, the programcode comprising: program code for pivotably applying a firstprocessor-controlled force to a contacting surface in communication witha substantially-spherical manipulandum to provide a haptic effect; andprogram code for applying a second processor-controlled force to thecontacting surface, wherein the second processor-controlled forcecomprises a first component normal to a surface of thesubstantially-spherical manipulandum and a second component tangentialto the surface of the substantially-spherical manipulandum.
 48. Thecomputer-readable medium of claim 47, wherein the program code forpivotably applying the first processor-controlled force comprisesprogram code for pivotably applying a substantially-normal,processor-controlled force, the substantially-normal, processorcontrolled force directed substantially normal to a surface of thesubstantially-spherical manipulandum.
 49. The computer-readable mediumof claim 47, wherein the second processor-controlled force is associatedwith the first processor-controlled force.
 50. The computer-readablemedium of claim 47, wherein the second processor-controlled force isassociated with a force associated with the substantially-sphericalmanipulandum.
 51. The computer-readable medium of claim 47, wherein thecontacting surface comprises a roller.
 52. The computer-readable mediumof claim 47, wherein the program code for pivotably applying the firstprocessor-controlled force to the contacting surface comprises programcode for applying the first processor-controlled force to a lever incommunication with the contacting surface.
 53. The computer-readablemedium of claim 47, further comprising program code for sensing amovement of at least one of the substantially-spherical manipulandum andthe contacting surface, and program code for varying at least one of thefirst processor-controlled force and the second processor-controlledforce in response.
 54. The computer-readable medium of claim 47, whereinthe substantially-spherical manipulandum comprises a trackball.